For turbine ring assemblies that are made entirely out of metal, it is necessary to cool all of the elements of the assembly, and in particular the turbine ring since it is subjected to the hottest streams. This cooling has a significant impact on the performance of the engine since the cooling stream used is taken from the main stream passing through the engine. In addition, using metal for the turbine ring limits the potential for increasing temperature in the turbine, even though increasing temperature would make it possible to improve the performance of aeroengines.
In an attempt to solve those problems, turbine ring sectors have been envisaged that are made out of ceramic matrix composite (CMC) material in order to avoid using a metal material.
CMC materials present good mechanical properties that make them suitable for constituting structural elements, and advantageously they conserve these properties at high temperatures. Using CMC materials has advantageously made it possible to reduce the cooling stream needed in operation and thus to increase the performance of turbine engines. Furthermore, using CMC materials advantageously makes it possible to reduce the weight of turbine engines and to reduce the high temperature expansion effect that is encountered with metal parts.
Nevertheless, the existing solutions that have been proposed may involve assembling a CMC ring sector with metal attachment portions of a ring support structure, these attachment portions being subjected to the hot stream. Consequently, the metal attachment portions are subjected to expansion when hot, and that can lead to applying mechanical stresses to the CMC ring sectors and to causing them to be weakened.
Also known are the following documents, which disclose turbine ring assemblies: GB 2 480 766, EP 1 350 927, US 2014/0271145, US 2012/082540, and FR 2 955 898.
There exists a need to improve existing turbine ring assemblies making use of CMC material in order to reduce the magnitude of the mechanical stresses to which the CMC ring sectors are subjected while the turbine is in operation.